As usual, I sit somewhere in the middle of a debate.
I certainly think players feel 'free' to do it to such an extent because it's in the culture of the sport and there's an attitude of 'us v them' about players, managers, fans v refs. And that could be improved more on the more professional level of managers, players and refs.
However, I also think too much is made of it because of all this stuff being pushed in the media that football players are 'role models', and have a duty to act and speak in a way that positively influences kids, etc. When, really, they are just competitive sports stars playing in a highly emotional, contact sport, often with big money on the line. It's understandable that they show emotion and react to situations, like everyone just watching the game is, let alone those directly involved in it.
So while I think an eye should be kept on it, and the officials are fine to act if it goes too far in terms of the rules of the sport, I do think too much is made of it by the media as if it's a major thing and one of the main responsibilities of the footballers to be 'good examples'. Stop (resentfully) holding their wages and fame against them and judge them as competitive sports people, in the heat of battle - not 'role models' out there to make social statements and setting examples for kids.